If you noticed uneven maturity or problem patches in your soybean fields this fall, you might be considering the cause. Soybean cyst nematode may be contributing to diminished root systems and yield loss, but testing is the only way to know for sure. While those problem areas are still top of mind, plan to sample them and use the results to guide management decisions for your next soybean rotation.

Soybean cyst nematode (SCN) (Figures 1 and 2) is the leading yield-limiting biological threat to soybean in North America and is estimated to cost U.S. producers $1.5 billion annually. SCN can cause yield losses of up to 30% without producing significant aboveground symptoms. As a result, many producers do not realize SCN is present and are not actively managing it in their fields.

As of 2026, SCN has been identified in 64 Nebraska counties (Figure 3). 

Effective management options are available, but the first step is determining whether SCN is present in a field. The end of the soybean growing season is the best time to test because SCN population levels are likely to be at their highest.

The Nebraska Soybean Board currently sponsors SCN sample analysis for samples collected from any Nebraska field. To participate, contact the UNL Plant and Pest Diagnostic Clinic for free soil sampling bags. Submit samples to the clinic using the following procedure.

Sampling Procedure

Collect SCN samples using a soil probe or spade. Gather at least 15–20 soil cores in a zigzag pattern across 10–20 acres. Collect soil from the root zone at a depth of 6–8 inches. Break up the cores and mix them thoroughly in a bucket, then place at least two cups of the composite sample in a bag for testing.

A sealable plastic bag will help prevent the sample from drying out. Marked SCN sample bags are also available from your local Nebraska Extension office or the UNL Plant and Pest Diagnostic Clinic.

Anything that moves soil can also move SCN. Because some parts of a field have a greater risk of SCN introduction or damage, consider sampling these areas first:

• Areas where soybean yielded less than expected.
• Areas of the field where soybean plants appeared stunted, yellow or defoliated earlier than the rest of the field.
• Low spots.
• Previously flooded areas.
• Field entryways.
• Field borders.
• Areas where sudden death syndrome (SDS) or brown stem rot (BSR) developed.

Submit samples to:

UNL Plant and Pest Diagnostic Clinic
448 Plant Sciences Hall
P.O. Box 830722
Lincoln, NE 68583-0722

Information to include on sample bag:

• Your name
• Address where you would like the results mailed
• Your email address
• Your phone number
• The field name or ID, for your reference
• The field’s recent crop history 

Management

Once SCN has been identified in a field, producers should follow four broad management recommendations.

The first is to rotate soybean varieties with different sources of SCN resistance. The most common resistance sources are PI 88788 and Peking. When possible, rotate among available resistance sources because SCN populations are evolving to overcome all resistance sources. Rotation can help preserve the effectiveness of existing resistance sources while new ones are developed.

The second management recommendation is to rotate soybean with to a non-host crop. Fortunately, corn, wheat and alfalfa are non-hosts that fit well within common Nebraska crop rotations. Although crop rotation alone will not eliminate SCN, it can help reduce population levels in the soil.

The third management recommendation is to consider using a nematode-protectant seed treatment. Many new seed-treatment products entering the market, but they should only be used in combination with an SCN-resistant soybean variety. Seed treatments should not be considered replacements for resistant varieties when managing SCN or other pathogens.

The final recommendation is to continue testing fields to monitor SCN population levels. Sampling every two to three years can help determine whether management practices are working. Fields without confirmed SCN should also be tested periodically so infestations can be detected early.

Many producers are experiencing some yield loss to SCN. Actively managing SCN populations provides an opportunity to protect that yield. Because this pest often produces no visible symptoms, soil testing is the only way to accurately identify and monitor it. If you do not remember the last time you tested, it is time to test again.

More Information

• Contact Nebraska Extension for more information.
• The SCN Coalition
• Soybean Cyst Nematode of Soybean, Crop Protection Network
• CropWatch Soybean Cyst Nematode Resources